Audiofrequency wireless fog-signal system



E. C. HANSON.

vAUDIOFREQUkNCY WIRELESS FOG SIGNAL SYSYEWI'.

APPLICATION FILED JUNE 4, 1918.

Patented Aug. 3% 19210 UNITED, STATES EARL c. HANSON, or LOS ANGELES, camronma,

ASSIGN'OR TO TITLE INSURANOE AND TRUST COMPANY A CORPORATION OF CALIFORNIA.

AUDIOFREQUENGY wmELEss'roG-sIeNAL SYSTEM.

To all whom it may concern:

Be it known that I, EARL C. HANSON, a citizen of the United States,"residing at Los Angeles, in-the county of Los Angeles and 5 State of California, have invented a new and useful Audiofrequency Wireless Fog-Signal System, of which the following is a specification.

My invention relates to the art of navigation, and the principal object of my invention is to provide means for indicating to a navigator the position of his ship with relation to other shipsor natural objects. By the useof my invention it is possible to navigate in heavy fogs. It is further possible to bring ships-through tortuous channels into harbor without the use of light houses or other visible signals and with a high factor of safety.

Referring to the drawings, which are for illustrativepurposes-onlyp Figure 1 is aside view of a ship in combination with one embodiment of my invention.

5 Fig. 2 is a section taken on a plane indi cated by the line 22, Fig. 1, this plane being viewed in the direction of the arrow.

Fig. 3 is a diagram of what maybe called the radiating apparatus.

0 A Fig. 4 is' a diagram of what may be called the receiving apparatus.

In the embodiment of my invention illustrated in these drawings, a ship 11 is shown, this ship floating on-the surface 12 of the 5 ocean or other body of water. For the purpose of indicating to those on the ship the position of the ship with relation to natural objects I. employ a pair of submarine cables 13 and 14. These cables are shown sup- 0 ported on floats 15 which are anchored by cables 16 to weights, 17, the purpose of the floats being to maintain the cables 13 and 14 at an approximately definite depth -Af below the surface 12. The cables 13 and 14 O'With the water in which t ey are submerged, and these cables are run'to a convenient point on shore at which point are located a high frequency generator 20 and a low frequency generator 21, these gen- 15 eratorsoperating at audio frequencies, that I Specification'df Letters Patent. I Patented Aug. 30, 1921. Applicatlbn filed June 4, 1918. Serial No. 23s,111.

is tosay, at frequencies below 10,000 cycles per second, but at frequencies sufficiently different from each other to allow the. difbeing connected to one of the cables 13 or 14, which in effect form antennae, as shown.

Located on the ship and preferably surrounding it onthe sides is an antenna 30.

This antenna may be insulated and submerged but is preferably looped around the side of the ship and connected to the primary 31 of a receiving transformer 32 having an iron core, one terminal of the primary 31 being grounded at 33, the other terminal being connected to the antenna 30. The secondary 34 of the transformer 32 has one terminal connected to a grid 35- of a vacuum bulb repeater 36, the vacuum bulb.

repeater 36 having a filament 37 energized by a filament battery 38. The filament 37 is also connected through a wire 39 with one terminal of the secondary 34 and with one terminal of a battery 40. The otherterminal of the battery 40 is connected through a milli-ammeter 41,-a telephone receiver 42 and a pair of vibrating magnets 43 and 44 with a plate 45 in the vacuum bulb repeater 36. The magnets 43 and 44 are provided with iron cores which act upon vibrating reeds 46 and 47. Each-of these vibrating reeds is so placed as to make contact through a battery48 and a lamp 49 when rapidly vibrating.

The method of operation of the invention above described is as follows:

The generators 20 and 21 are in continuous operation at all times when it is desired to utilize the invention and they impress an electro-static charge between the ground and the submerged wires 13 and 14. This electro-static charge sets-up an electro-stat1c field which includes the antenna 30 causing a current to flow through the primary -31-to the ground. This current induces a potential in the secondary 34 which controls a much heavier current, passingfrom the plate 45. to the filament 37 in: the vacuum bulb repeater 36, this heavy current also passing throughl the vibrating magnets 43 and 44, the telephone receiver 42 and the ammeter 41. The frequency of this current will depend upon which of the wires 13 and 14 the ship is closest to. In the position shown in Fig. 2 there will be two superimposed frequencies flowing through the vibrating magnets 43 and 44, one of these be in due to the generator 20 and the other belng due to the generator 21. As a result both the reed 46 and the reed 47 will vi brate and both of the lights 49 will. be lighted. At the same time a musical note based on two frequencies will be heard in .the receiver 42 and the relative strength of the current flowing can be observed on the ammeter 41. The navigator will, therefore, know that he is close to both of the wires, and if the ammeter 41 is suitably calibrated he Will know very closely his distance from these wires.

As the vessel 11 recedes from either of the wires 13 or 14 the strength of the induced current produced by that wire through the ammeter 41, for example, will decrease and at the same time the musical note corresponding to that frequency will become relatively less. Should the ship cross over either of the wires entirely so that it were on the opposite side, the navigator would practically hear only one note and'the ammeter would indicate the distance from that wire. It will be seen that the submerged wires 13 and 14 would, therefore, form what might be termed a lane which the navigator would have no difiiculty in following by a proper observation of the ammeter 41 and the lights 49, the roper position of the ship being between t e wires 13 and 14 in which position both notes would be heard at about equal loudness. These notes would be heard regardless of fog or other conditions and the indications would not be interfered with by radio waves or by other audio waves from sources located at a distance from the wires 13 and 14. The radio waves would be entirely ironed out by the iron core of the transformer 32 and inductive interference from power transmission lines on shore would be negligible.

In some cases the wires 13 and 14 might be placed on the shore and might serve not as signals to be followed but as warning signals, the visible signal given by the lights 49 or the audiblesignal given by the telephone receiver 42 being heard only as the ship approaches a dangerous position near the shore. By the use-of my invention it would be possible b running a warning signal wire alon a cangerous coast to efi'ectually warn ships which approach that coast even in dense fogs or under other conditions which would render visible signals uncertain and unreliable.

I claim as my invention: 1. In a system of navigation, the combination of a submerged cable energized from on shipboard and adapted to be affected by the energy received from the cable, a vacuum tube amplifier associated with said collector system, and a visible indicator actuated by the received energy.

3. In a system of navigation, the combination of a submerged cable arranged in a ship channel and energized by a source of adiofrequency energy, and an apparatus on ship board afi'ected b the field of force emanating from said ca le, said apparatus comprising a collector system, a vacuum tube amplifier associated with said collector system,

and visible and audible signals actuated by said amplified energy.

4. In a system of navigation the combination of a submerged cable arranged in a channel and energized by a source of audiofrequency electric energy, and apparatus on shipboard comprising a collector system, a.

vacuum tube amplifier associated therewith, and means for visibly and audibly indicating the relative position of the ship to the cable.

5. In a system of navigation, the combination with a plurality of cables arranged in a channel, and energized by sources of different audio-frequency, of apparatus on shipboard comprising a collector system, a vacuum tube amplifier associated with said collector system, and visible indicators selectively actuated by the received energy in accordance with the relative position of the ship to said cables.

6. In a system of navigation, the combination of a submerged cable arranged in a channel and energized by a source of audiofrequency energy, with apparatus on shipboard comprising a collector system, a vacuum tube amplifier having its input circuit inductively coupled with said collector system, and an indicating instrument arranged in the output circuit thereof and calibrated to show maximum response when the distance between the collector system and the cable is a minimum.

In testimon whereof,'I have hereunto set EARL C. I-IANSGN. 

